JP2015106597A - Encapsulation structure of video output device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical module capable of preventing moisture to infiltrate inside due to a change in environmental temperature, making dew condensation inside the optical module hardly to occur, and achieving high reliability.SOLUTION: A drying layer 107 is provided at a boundary surface between an optical module cover 102 or a plane packing 103, and a base 104. Since moisture may be absorbed by the drying layer, moisture hardly infiltrates into the inside of a module from the boundary surface.

Description

  The present invention relates to a sealing structure for optical components of a video output device.

As background art of this technical field, there is JP-A-2007-210627 (Patent Document 1). This gazette states that “a moisture-proof housing having a storage portion that contains a stored item and is shielded from the outside air, and a moisture-proof case that is provided in the moisture-proof case and has elasticity and moisture resistance. Pressure difference reducing means for reducing the difference between the pressure and the atmospheric pressure ”. Moreover, there exists Unexamined-Japanese-Patent No. 2008-239017 (patent document 2). This publication provides “a vehicle-mounted camera that can keep the camera view well by preventing condensation and fogging inside the lens cover with a simple configuration without providing a heater, a temperature sensor, a blower, and the like. For this purpose, a camera housing portion for accommodating the CCD camera, a lens cover disposed on the front side of the CCD camera, a space between the lens cover and the CCD camera, and the lens cover 5 are provided. It is provided with a communicating path that communicates with the outer space of the water, and a moisture-permeable waterproof material that blocks moisture and passes only moisture is disposed in the communicating path.

JP 2007-210627 A JP 2009-182922 A

  FIG. 1 and FIG. 2 show schematic diagrams of an RGB module, which is a video output device, as an example. FIG. 1 is an example of a top view of the RGB module, and FIG. 2 is an example of a side view of the RGB module.

  In the RGB module, each optical component is fixed to the casing using an adhesive. The main optical components of the RGB module include a laser diode (green) 103, a laser diode (red) 104, a laser diode (blue) 105, an RGB composite mirror 106, an RGB composite mirror 107, and a MEMS mirror 108.

  Since the RGB module is also used, for example, in a vehicle, it is required to have high reliability that can withstand harsh environments such as high temperature and high temperature and humidity as compared with conventional modules. In this RGB module, since a laser diode (LD) is mounted as shown in FIG. 1, LD degradation or the like easily occurs due to heat generation. In addition to the heat generated by the LD itself, for example, when it is used in a car or installed on a dashboard, there is a risk that the ambient environment temperature becomes high and the LD does not light up. As a means for preventing this, a Peltier element is mounted as shown in FIGS. 2 and 3 to force cooling.

  Therefore, if there is more moisture than necessary inside the module, the outside (environment) becomes hot (for example, 55 to 85 ° C.) when the inside of the optical module is cooled, and dew condensation tends to occur inside. In particular, when condensation occurs on the exit window or MEMS mirror of light deeply related to normal operation, there are problems such as malfunction of the MEMS mirror and problems such as blurring of the projected image due to fogging of the exit window.

  If the example of the solution means of this invention is given, a dry layer will be provided, for example in the interface of the flat packing for sealing an optical module.

  Further means and effects of the present invention will become apparent from the following examples.

  In the RGB module, by providing a structure having a dry layer at the interface between the packing and the module, it is possible to prevent moisture from entering from the packing interface into the module and achieve high reliability.

It is an example of the top view of a RGB module. It is an example of the side view of a RGB module. It is a general view of the prior art example of an RGB module. It is a side view of the prior art example of an RGB module. 1 is an overall view of Example 1. FIG. 1 is a side view of Example 1. FIG. 3 is a top view of Example 1. FIG. 6 is a side view of Example 2. FIG. 6 is a side view of Example 3. FIG. 10 is a top view of Example 3. FIG. 6 is a top view of Example 4. FIG. 10 is a side view of Example 5. FIG. 10 is a top view of Example 6. FIG. It is a side view of Example 6. 10 is an overall view of Example 7. FIG. 10 is a side view of Example 7. FIG. 10 is a top view of Example 7. FIG.

  Embodiments will be described below with reference to the drawings.

  A first embodiment will be described with reference to FIGS. In the RGB module as shown in FIG. 1, an optical module LD 201, a MEMS mirror 204, and a company office window 205 are mounted on an optical module casing 201, and a flexible printed circuit for transmitting a control signal for the MEMS mirror 207. (FPC) 205 is installed. The mirror and lens are not shown in the figure.

  In this way, since three LDs 203 that generate large amounts of heat are mounted, the structure is very easy to collect heat. Therefore, as shown in the side view of FIG. 2, the LD 203 can be cooled by adopting a structure in which the Peltier element (for LD cooling) 206 is attached immediately below the optical module housing 201. In combination with its own heat generation, for example, when it is used in a car or installed on a dashboard, the surrounding environmental temperature becomes high, so that it is difficult for problems such as the LD not to light up.

  However, it has been found that by using the Peltier element (for LD cooling) 206 in a sealed space, the inside may condense and adhere to the optical component, thereby causing a problem. This is because if there is more moisture than necessary inside the module, the inside of the optical module is cooled, but the outside (environment) is at a high temperature (55 to 85 ° C), and moisture above the saturated water vapor amount is inside. Because of this, it is easy for condensation to occur. " In particular, when dew condensation occurs on the light exit window or the MEMS mirror, which is deeply related to normal operation, malfunction of the MEMS mirror, or a problem such as blurring of the projected image due to fogging of the exit window occurs. As a structure for preventing condensation, there are methods described in Patent Documents 1 and 2. However, these require extra power and control for controlling the atmospheric pressure.

  An object of the present invention is to prevent water from entering in a space-saving manner without requiring any electric power.

  There are two cases where moisture permeates through the inside of the flat packing material (silicone, rubber, etc.) and when the water enters from the interface portion in contact with the flat packing as shown in FIG. In particular, it has been found that the amount of moisture entering from the interface is large. Therefore, as shown in FIGS. 5 to 7, by providing a dry layer 107 at the interface between the flat packing 103 and the base 104, it was decided to prevent moisture from entering from the interface. FIG. 5 is an example of an overall view of the first embodiment, and a cover is attached by screwing at four positions. If the number of the screws is symmetrical, there is no problem even if the number increases, but it is desirable to fix with four or more screws.

  6 is an example of a side view in the first embodiment, and FIG. 7 is an example of a top view in the first embodiment. In FIG. 6, a cross section of the flexible printed circuit board (FPC) 105 is shown. However, as shown in FIG. 7, the packing and the dry layer are provided so as to wrap around the optical module casing 108. Infiltration is suppressed.

  As the desiccant contained in the dry layer, a solid desiccant such as silica gel, calcium chloride, diphosphorus pentoxide is desirable. A sheet-like desiccant can also be used. In addition, the above desiccant may cause re-release of moisture, but it becomes possible to prevent re-release of water by using a desiccant that forms a complex with water by chemical reaction. .

  As described above, intrusion of moisture from the interface between the flat packing 103 and the base 104 in the first embodiment can be prevented by providing the dry layer 107, and condensation of optical components inside the optical module does not occur. The effect that can be realized.

A second embodiment will be described with reference to FIG. The same reference numerals as those in FIG. 6 of the first embodiment denote the same components.
FIG. 8 is a side view of the second embodiment of the RGB module according to the second embodiment. In FIG. 8, the dry layer provided only at the interface between the flat packing 103 and the base 104 in FIG. 6 is also attached to the module cover 102. In this way, in Example 1, it was possible to prevent moisture from entering only at one of the interfaces, but it was possible to prevent moisture from entering at either interface and prevent moisture from entering. It becomes.

  Further, since the flat packing material is often a rubber-like material such as silicone or elastomer, it needs to be compressed with the screw 101. Therefore, when the width of the dry layer 107 is larger than that of the flat packing 103, when the pressure is applied by the screw 101, the dry layer 107 protrudes into the dry layer 107, and there is a possibility that the performance as the packing does not appear.

  Therefore, as shown in FIG. 8, when the width of the packing is A and the width of the dry layer is B, A must always be larger than B. Considering the tightening force of the flat packing screw, the flat packing 103 should have the base 104 and the ground contact area as large as possible. Therefore, the width B of the dry layer is preferably as small as possible with respect to A, and B is preferably less than half of A. .

  Similarly, when the dry layer 107 is provided on the module cover 102 as shown in FIG. 8, it is desirable that the width of the packing is smaller than the width of the dry layer.

  As described above, by providing the dry layer 107 on the base 104 and the module cover 102 in the second embodiment, it is possible to prevent moisture from entering the inside, and it is difficult for condensation inside the optical module to occur.

  A third embodiment will be described with reference to FIGS. The same reference numerals as those in FIG. 6 representing the first embodiment denote the same components.

  FIG. 9 is a side view of a structural example in Example 3, and FIG. 10 is a top view of the structural example in Example 3 according to the present invention.

  In Example 3, the shape of the dry layer 107 as described in Example 1 and Example 2 is formed in a staggered pattern as shown in FIG. By forming the dry layer 107 in a staggered pattern, the width of the dry layer 107 can be reduced, an even pressure is applied to the flat packing 103, and the airtightness by tightening the screw 101 can be maintained. .

  In Example 3, although the shape which looked at the upper surface of the dry layer 107 described that it was a staggered lattice shape, a mesh-like lattice etc. are also considered.

  A fourth embodiment will be described with reference to FIG. The same reference numerals as those in FIG. 6 representing the first embodiment denote the same components. FIG. 11 is a top view of a structural example according to the fourth embodiment.

  The fourth embodiment is substantially the same as the first and second embodiments, but is an example in which two or more dry layers 107 are provided in the same plane packing 103.

  Thus, by dividing the dry layer into two or more, it is possible to reliably prevent moisture entering the packing interface that could not be prevented by the dry layer closer to the outside with the second dry layer. It becomes like this.

  Moreover, although it is the same as Example 2, 3, the pressure of packing can be made uniform by making the sum total of the width | variety of two or more dry layers smaller than the width | variety of packing, and to the inside of a module. Can prevent the intrusion of moisture.

  A fifth embodiment will be described with reference to FIG. The same reference numerals as those in FIG. 6 representing the first embodiment denote the same components.

  FIG. 12 is a side view of a structural example according to the fifth embodiment.

  In Example 5, the dry layer 107 as shown in Examples 1 to 4 is formed into a dry sheet 109. The thickness of the dry sheet 109 is desirably thin, but is desirably 0.5 mm or less. When it becomes larger than this, a space is generated at the end of the dry sheet, and moisture easily enters.

  By using the dry sheet 109, it is not necessary to process the dry layer as in the first to fourth embodiments into the module cover 102 and the base 104, so that man-hours can be saved.

  Further, since the sheet and the packing can be in close contact with each other as compared with the dry layer, it is presumed that pressure due to screwing is easily applied and the sealing performance of the packing is improved.

  A sixth embodiment will be described with reference to FIGS. The same reference numerals as those in FIG. 6 representing the first embodiment denote the same components.

  FIG. 13 is a top view of a structural example in the sixth embodiment, and FIG. 14 is a top view of a structural example in the fifth embodiment.

  In Example 6, two or more packings are used, and a dry layer is provided between the packings. In this way, by using two or more packings, by providing a dry layer, not only the interface with the packing but also moisture that passes through the inside of the packing can be absorbed by the dry layer. Moisture does not easily penetrate into the module.

  At this time, when a desiccant is used, it is desirable to provide a groove between the packings to prevent the desiccant from spreading as shown in FIG. In the case of using a dry sheet, the groove is not necessary, and the installation location may be anywhere between the packings.

  A seventh embodiment will be described with reference to FIGS. The same reference numerals as those in FIG. 6 representing the first embodiment denote the same components.

  15 is an overall view of a structural example in the seventh embodiment, FIG. 16 is a side view of the structural example in the seventh embodiment, and FIG. 17 is a top view of the structural example in the seventh embodiment.

  The overall view as shown in FIG. 15 is the same as in the first to sixth embodiments. However, as shown in FIG. 16, the filter 111 and the exhaust port 110 are provided in the dry layer.

  As a material of the filter 111, a filter having a function that does not receive moisture from the outside and can release water molecules raised by the moisture absorbed by the desiccant 106 in the drying layer 107 is used. For example, it is desirable to use a resin or cloth that has fine holes close to the size of water molecules (about 0.38 nm).

  In addition, the attachment of the filter requires the exhaust port 110 to be completely blocked, and it is desirable to use an adhesive.

  As described in FIGS. 1 and 2, the optical module is equipped with a Peltier element for cooling the LD. The LD side is cold, but the base and module cover on which the module is mounted are hot. ing. Accordingly, the drying layer 107 is always at a high temperature during the operation of the module, and the inside of the sealed drying layer 107 is always in a high pressure state, so that the exhaust is efficiently performed.

  In addition, when a desiccant that absorbs moisture and does not re-release is used, the use of such an exhaust port 110 and filter 111 releases internal moisture even when moisture absorption is saturated. be able to.

  FIG. 17 is a top view of the seventh embodiment, and only one filter 111 and exhaust port 110 are provided for the dry layer. In order to improve the exhaust efficiency of the dry layer 107, the exhaust gas is exhausted. It is desirable to provide one or more mouths.

  As described above, even when the humidity of the drying layer 107 increases due to the re-release of the moisture absorbed by the desiccant 106 as in Example 7, the structure allows the moisture to be discharged to the exhaust port 110 through the filter 111. By doing so, it is possible to prevent moisture from entering the optical module.

  As mentioned above, although the example about the optical module was demonstrated, this invention is not limited to said embodiment, For example, it can apply also to products like a large sized projector and a communication optical module.

201 Optical module housing
202 Module cover
203 Laser diode
204 MEMS mirror
205 Mirror 206 Flexible Printed Circuit Board (FPC)
207 Peltier element (for LD cooling)
208 Exit window
209 video
101 Screw 102 Module cover 103 Flat packing 104 Base 105 Flexible printed circuit board (FPC)
106 Desiccant 107 Drying layer 108 Optical module housing 109 Drying sheet 110 Exhaust port 111 Filter

Claims (7)

An optical module having an optical window, a laser diode, and an optical component mounted thereon and sealed using a flat packing, wherein an optical module has a dry layer at an interface between the flat packing and the module housing. 2. The optical module according to claim 1, wherein at least both the flat packing and the base and cover of the module have a dry layer. 3. An optical module according to claim 1, wherein the width of the dry layer is smaller than the width of the flat packing. 4. The optical module according to claim 1, wherein the dry layer has a staggered lattice structure. 5. The optical module according to claim 1, wherein two or more drying units are provided at the interface of the same flat packing. 6. The optical module according to claim 1, wherein at least two flat packings are used, and a dry layer is provided between adjacent flat packings. 7. The optical module according to claim 1, wherein at least one exhaust port having a filter attached to the dry layer is provided.

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